Linear regression analysis illustrated a progressive increase in gene expression as paternal age increased for eleven genes, two of which show an association with brain function; ITGA2 has been linked to axonogenesis [60] while SLC25A27 is involved metabolism in the brain, and is implicated in autism spectrum disorder as well as a possible connection to schizophrenia [61, 62]. This evidence concerns the gene ITGA2 and schizophrenia.